Long-term and late seizure outcome after surgery for temporal lobe epilepsy

Although surgery for temporal lobe epilepsy (TLE) harbours a good prognosis, post-operative seizures may occur. Long-term, post-operative seizure follow-ups are rare but necessary to properly define outcome.

Longitudinal, long-term, post-operative seizure follow-up in TLE patients with outcome analysed using Engel's classification. Three groups were considered according to the type of resection: isolated amygdalohippocampectomy (IAH), further divided into anterior and complete, AH plus focal neocortical resections (AH + FR) and focal neocortical resections (FR).

Eighty-nine patients were enrolled (61 in the IAH group, 24 in the AH + FR group, and four in the FR group), with a mean follow-up time of 46.7 months. For the three groups together, 90.9% and 86.7% of the patients were in Engel class I for six months and five years, respectively. Kaplan-Meir analysis of the IAH and AH + FR groups showed that, while 82.2% of patients of the IAH group tended to remain in class I within 84 months after surgery, 86.7% of the AH + FR group tended to remain in class I within 12 months. Kaplan-Meier analysis of the IAH sub-groups showed that more patients (91.0%) with anterior resection tended to remain in class I, although for a longer period of time (36 months), compared to those with complete resection (84.0% of patients and 12 months, respectively). For the IFR group, only three patients were in Engel class I for long-term follow-up.

High rates of seizure freedom were obtained and stably maintained for years. The reasons for better long-term prognosis of the anterior IAH group are so far unclear, the IFR group was too small to draw any conclusive data.